The field of the invention generally relates to mailboxes, and more specifically to mailboxes having improved structural rigidity and improved impact resistance over common mailboxes.
Curbside mailboxes used in the United States today must undergo and pass testing against United States Postal Service (USPS) Standard 7, and be approved by the United States Postal Service (“USPS”) engineering team. Section 4 of USPS Standard 7 (currently revision C) includes two requirements of particular interest, namely Section 4.8 (Structural Rigidity) and Section 4.9 (Impact Test).
USPS Standard 7 identifies the static load and impact locations for these tests, describing how to perform them, and how to evaluate compliance. A paraphrased excerpt follows, with reference to FIG. 1. The “Position Numbers” (#1-#6) shown in FIG. 1 are referenced throughout this patent application as such. An excerpt from USPS Standard 7 is provided below:
1. Strength Test:                a. Apply the load #1 onto bolster plate as in figure.        b. Hold for 1 minute.        c. Remove load.        d. Measure permanent deformation. Permanent deformation must not exceed the amount stated in the table.        e. Repeat for locations #2 through #5.        
PositionMax. Deformation (inches)Load (lbs)1⅛2002⅛2003⅛504⅛505⅛100
2. Impact Test:                a. Drop 10 lb weight onto position #3 from a height of 3 feet using a 2″×2″ bolster plate.        b. Observe closely inside and outside for any perforation (hole), crack, sharp edges, and door operation. There must not be any such perforations, cracks, or sharp edges, and the door must still operate normally.        c. Repeat for position #4.        